Structure of driving member of engine valve

ABSTRACT

An engine includes a camshaft carrying a first intake cam, a second intake cam, and an exhaust cam for selectively driving an intake valve driving member and an exhaust valve driving member, which in turn drive an intake valve and an exhaust valve. The intake valve driving member includes first and second driving members, which form push rollers respectively in engagement with the first and second intake cams and a pressing section in engagement with the intake valve. The first and second driving members form bores communicating each other to form a hydraulic cylinder. First and second pistons are movable within the bores to selectively set the first and second driving members in a condition of being allowed to operate independently or in combination with each other.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a driving member of valve of engine, and more particularly to a structure of valve driving member of engine that simplifies engineering of variable lift of an engine valve.

DESCRIPTION OF THE PRIOR ART

FIG. 1 of the attached drawings shows a conventional structure of valve variable-lift mechanism for an engine 1, wherein first and second driving members 21, 22 are arranged above an engine valve 2. The second driving member 22 is a multiple-link assembly. The first and second driving members 21, 22 may individually drive the engine valve 2 to realize variation of lift stroke of the engine valve 2. In other words, when the engine valve 2 is driven by the first driving member 21, the engine valve 2 is of a small lift opening condition, while when the engine valve 2 is driven by the second driving member 22, the engine valve 2 is of a large lift opening condition. As such, switching of intake and exhaust valves can be realized for different lifts of engine valve 2 according to rotational speeds of the engine 1.

The conventional structure of valve variable-lift mechanism for the engine 1 described above uses the first and second driving members 21, 22 arranged above the engine valve 2 to individually drive the engine valve 2. Although this is effective to realize switching of intake and exhaust valves for different lifts of engine valve 2 according to the rotational speeds of the engine 1, yet the second driving member 22 is of a multiple-link assembly, which is complicated in structure and requires quite an amount of space for operation. Thus, the cylinder head 1 a of the engine 1 must be enlarged in order to provide a sufficient amount of space for the operation of the second driving member 22. Enlarging the cylinder head 1 a of the engine 1 will certainly increase the cost of the engine 1 and also increase complication of engineering for the engine 1. For a motorcycle or scooter, the amount of space provided for accommodating an engine 1 is very limited. Thus, it is desired to provide a structure-simplified valve variable-lift mechanism for engines and this is a major challenge of the motorcycle/scooter industry.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a structure of driving member of valve of engine, wherein the engine comprises a crankcase, a cylinder block mounted on the crankcase, and a cylinder head mounted on the cylinder block. The cylinder head comprises an intake port and an intake valve and an exhaust port and an exhaust valve, and an oil control valve. A camshaft seat is arranged between the intake valve and the exhaust valve. The camshaft seat comprises a camshaft that is driven by a timing chain. The camshaft comprises a first intake cam, a second intake cam, and an exhaust cam mounted thereto. Through the first intake cam, the second intake cam, and the exhaust cam, the camshaft, when put in rotation, drives an intake valve driving member or an exhaust valve driving member, and further, through the intake valve driving member or the exhaust valve driving member, the intake valve or the exhaust valve is caused to take a lift for intake or exhaust operation. The intake valve driving member comprises a first driving member and a second driving member. The first driving member forms a positioning hole, a bore, and a push roller and the second driving member forms a positioning hole, a bore, a push roller, and a pressing section. The push roller of the first driving member is in engagement with the first intake cam and the push roller of the second driving member is in engagement with the second intake cam. Further, the pressing section of the second driving member is in engagement with the intake valve. The bore of the first driving member and the bore of the second driving member are in communication with each other to form a hydraulic cylinder. The hydraulic cylinder has two ends respectively closed by closure caps. The hydraulic cylinder receives therein a spring and first and second pistons. As such, the first driving member and the second driving member can be selectively driven to operate independent of each other or in combination with each other to vary the lift of an engine intake valve thereby simplifying the engineering of variable lift for engine intake vale.

Another objective of the present invention is to provide a structure of driving member of valve of engine, wherein a position-constraining mechanism is arranged above the cylinder head and the position-constraining mechanism comprises a position-constraining rod, a spring, and a pressure relief hole, whereby with the position-constraining mechanism being in pushing engagement with the first driving member and the second driving member the positioning bar, it is ensured that the bores of the first and second driving members can be set at predetermined locations.

A further objective of the present invention is to provide a structure of driving member of valve of engine, wherein the first driving member and the second driving member comprise positioning bars that are located between the positioning holes and the pressing section and the bores of the first and second driving members are located between the push rollers and the positioning holes and located above a center-connection line connecting between centers of the push rollers and the positioning holes whereby the overall height of the cylinder head is effectively reduced.

The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic view showing a conventional cylinder head.

FIG. 2 is a perspective view illustrating an engine cylinder head according to the present invention.

FIG. 3 is a cross-sectional view of a portion of the cylinder head according to the present invention.

FIG. 4 is a perspective view illustrating a camshaft according to the present invention.

FIG. 5 is a top view of the cylinder head according to the present invention.

FIG. 5A is an enlarged view of a circled portion of FIG. 5.

FIG. 6 is a perspective view illustrating an exhaust valve driving member according to the present invention.

FIG. 7 is an exploded view illustrating an intake valve driving member according to the present invention.

FIG. 7A is a cross-sectional view of a first piston according to the present invention.

FIGS. 8 and 9 are schematic views illustrating the operation of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

Referring to FIG. 2, the present invention provides an engine 3, which comprises a crankcase 31, a cylinder block 32 that is mounted on the crankcase 31, and a cylinder head 33 that is mounted on the cylinder block 32.

The crankcase 31 comprises a crankshaft (not shown) arranged therein. The crankcase 31 comprises an oil pump 311 arranged therein. The oil pump 311 pumps oil to a primary oil supply passage 312. The primary oil supply passage 312 extends from the crankcase 31 through the cylinder block 32 to communicate an oil control valve 4 that is mounted to the cylinder head 33.

The cylinder block 32 is mounted on the crankcase 31 and receives a timing chain 5 to extend therethrough. The cylinder block 32 comprises a timing chain tensioner 51 that is arranged at a side corresponding to an intake port 331 of the cylinder head 33.

The cylinder head 33 comprises the intake port 331 that is arranged at an intake side and an intake valve 332 and an exhaust port 333 that is arranged at an exhaust side and an exhaust valve 334. Referring to FIGS. 2, 3, 4, 5, and 5A, the cylinder head 33 comprises a camshaft seat 335 that is integrally formed between the intake valve 332 and the exhaust valve 334. The camshaft seat 335 comprises a camshaft 336 that is driven by the timing chain 5. The camshaft 336 comprises a first intake cam (high lift cam) 3361, a second intake cam (low lift cam) 3362, and an exhaust cam 3363 mounted thereto. Through the first intake cam 3361, the second intake cam 3362, and the exhaust cam 3363, the camshaft 336, when in rotation, may drive an intake valve driving member 6 and an exhaust valve driving member 7 of the intake valve 332 and the exhaust valve 334. Referring to FIGS. 3, 5, 5A, and 6, the exhaust valve driving member 7 has an end forming a pressing section 71, which is in engagement with the exhaust valve 334 and has an end forming a gap adjusting member 711, and an opposite end forming a push roller 72, which is in engagement with the exhaust cam 3363. A bearing sleeve 73 extends sideways from a side of the exhaust valve driving member 7 for receiving the extension of a shaft rod 74 therethrough. Through the shaft rod 74, the exhaust valve driving member 7 is securely positioned on the camshaft seat 335, whereby the exhaust cam 3363 of the camshaft 336 may drive the push roller 72 to have the pressing section 71 pressing the exhaust valve 334 for opening the exhaust valve to discharge exhaust gas. A gap between the pressing section 71 and the exhaust valve 334 can be adjusted through the gap adjusting member 711 in order to ensure the exhaust valve 334 has a desired lift stroke. Further, referring to FIGS. 3, 5, 5A, 7, and 7A, the intake valve driving member 6 comprises a first driving member 61 and a second driving member 62. The first driving member 61 forms in a front portion thereof a positioning hole 611, a positioning bar 612 being arranged to project from a front lower side of the positioning hole 611, and also forms a through bore 613 at a location behind the positioning hole 611, a push roller 614 being arranged behind the bore 613. Corresponding to the first driving member 61, the second driving member 62 forms, in sequence, a positioning hole 621, a positioning bar 622, a through bore 623, and a push roller 624. Further, the second driving member 62 comprises a pressing section 625 extending from a front side of the positioning hole 621 and the pressing section 625 has a front end forming a gap adjusting member 6251. The push roller 614 of the first driving member 61 is set in engagement with the first intake cam 3361 of the camshaft 336, while the push roller 624 of the second driving member 62 is in engagement with the second intake cam 3362 of the camshaft 336. Further, the pressing section 625 of the second driving member 62 is in engagement with the intake valve 332. A gap between the pressing section 625 and the intake valve 332 can be adjusted through the gap adjusting member 6251 in order to ensure that the intake valve 332 has a desired lift stroke. Further, with a shaft rod 63 received through the positioning holes 611, 621, the first driving member 61 and the second driving member 62 are securely positioned on the camshaft seat 335, whereby the first driving member 61 and the second driving member 62 are reciprocally rotatable about a center defined by the shaft rod 63. Further, as shown in FIG. 3, the positioning bars 612, 622 of the first driving member 61 and the second driving member 62 are respectively arranged at locations between the positioning holes 611, 621 and the pressing section 625. The bores 613, 623 of the first driving member 61 and the second driving member 62 are located between the push rollers 614, 624 and the positioning holes 611, 621 and are located above a center-connection line A connecting between centers of the push roller 614, 624 and the positioning holes 611, 621 so as to effectively reduce the overall height of the cylinder head 33. Referring to FIGS. 5, 5A, 7, 7A, 8, and 9, the bore 613 of the first driving member 61 and the bore 623 of the second driving member 62 are arranged to connect to and communicate each other to collectively form a hydraulic cylinder 64. The hydraulic cylinder 64 has opposite ends that are respectively closed and sealed by closure caps 641 a, 641 b. Each of the closure caps 641 a, 641 b forms a projecting peg 6411 a, 6411 b extending inward of the hydraulic cylinder 64. The hydraulic cylinder 64 receives therein a spring 642 and a first piston 643 and a second piston 644, which are hydraulically movable by oil pressure. The hydraulic cylinder 64 is connected through driving oil passages 65, 66 to the oil control valve 4 in order to receive hydraulic power therefrom. Further, the first piston 643 has two ends respectively forming a first recess 6431 and a second recess 6432 for the purposes of reducing weight of the first piston 643 and thus enhancing movability of the first piston 643 within the hydraulic cylinder 64. The first recess 6431 is shaped to receive the projecting peg 6411 a of the closure cap 641 a therein and the projecting peg 6411 b of the closure cap 641 b is engageable with an end of the second piston 644, whereby the first piston 643 and the second piston 644 are spaced from the ends of the hydraulic cylinder 64 by distances to allow oil flowing through the driving oil passages 65, 66 into the hydraulic cylinder 64 may reliably move the first piston 643 and the second piston 644. Further, with the projecting pegs 6411 a, 6411 b of the closure caps 641 a, 641 b, the first piston 643 and the second piston 644 are positionable at predetermined locations during their operations so as to ensure the movability of the first piston 643 and the second piston 644 within the hydraulic cylinder 64. Further, the cylinder head 33 is provided, at a location below the positioning bars 612, 622, with a position-constraining mechanism 337. The position-constraining mechanism 337 comprises a position-constraining rod 3371, a spring 3372, and a pressure relief hole 3373. The position-constraining mechanism 337 is provided for supporting pushing engagement of the positioning bars 612, 622 in order to ensure that the bore 613 of the first driving member 61 and the bore 623 of the second driving member 62 can be set at predetermined locations. Further, when the position-constraining mechanism 337 is acted upon by undue pushing forces applied by the positioning bars 612, 622, the pressure relief hole 3373 is timely opened to release pressure in order to ensure the movability of the first piston 643 and the second piston 644 within the hydraulic cylinder 64.

To practice the present invention, as shown in FIGS. 2, 3, 8, and 9, the oil pump 311 arranged in the crankcase 31 pumps oil to the primary oil supply passage 312, which extends from the crankcase 31 through the cylinder block 32 to communicate the oil control valve 4 that is mounted to the cylinder head 3, wherein the oil control valve 4 supplies the oil into the driving oil passages 65, 66 of the cylinder head 33 to feed into the hydraulic cylinder 64. Further, as shown in FIGS. 8 and 9, through detection of traveling condition of a vehicle by an ECU (not shown) of the engine 3, if it is determined that the engine valve requires only low lift opening, the ECU of the engine 3 instructs the oil control valve 4 to feed the oil through the driving oil passage 65 into the hydraulic cylinder 64, as shown in FIG. 8, whereby through the oil pressure and a spring force of the spring 642, the first piston 643 and the second piston 644 are moved in a direction toward the first driving member 61. The oil, after flowing through the driving oil passage 65 into the bore 621 of the second driving member 62, is guided by the projecting peg 6411 of the closure cap 641 a and the first piston 643 into the recess 6431 of the first piston 643, and at the same time, the oil contained in the first driving member 61 is forced to discharge through the driving oil passage 66, whereby the second piston 644 is moved to locate within the first driving member 61 and is positioned at a predetermined location by the projecting peg 6411 b of the closure cap 6411 b at the side corresponding to the first driving member 61 and the first piston 643 is located in the second driving member 62. Under this condition, the first driving member 61 and the second driving member 62 are allowed to rotate independent of each other. Since the pressing section 625 at the front end of the second driving member 62 is in engagement with the intake valve 332 and the push roller 624 at the rear end of the second driving member 62 is in engagement with the second intake cam (low lift cam) 3362 of the camshaft 336, the intake valve 332 of the engine 3 is set in a low lift opening condition. Further; when the engine 3 is switched, due to change of vehicle traveling condition, to a high lift opening condition for the intake valve, the ECU of the engine 3 instructs the oil control valve 4 to feed oil through the driving oil passage 66 into the hydraulic cylinder 64, as shown in FIG. 9, whereby the oil flows through the driving oil passage 66 into the bore 613 of the first driving member 6 and at the same time, the oil contained in the bore 623 of the second driving member 62 is discharged. Through the oil pressure, the first piston 643 and the second piston 644 are moved in a direction toward the second driving member 62 to have the first piston 643 located in the second driving member 62 and through the constrain imposed by the projecting peg 6411 a of the closure cap 641 a of the second driving member 62, the first piston 643 and the second piston 644 are located at predetermined locations where the second piston 644 is set between the first driving member 61 and the second driving member 62, whereby the first driving member 61 and the second driving member 62 are coupled to each other. Since the push roller 614 at the rear end of the first driving member 61 is in engagement with the first intake cam (high lift cam) 3361 of the camshaft 336 and the pressing section 625 at the front end of the second driving member 62 is in engagement with the intake valve 332, the second driving member 62 is moved by the first driving member 61 to set the intake valve 332 to a desired high lift opening condition according to the lift of the first intake cam (high lift cam) 3361. As such, variable valve lift of the engine 3 can be realized.

Efficacies of the present invention are that the camshaft 336 is provided with the first intake cam 3361, the second intake cam 3362, and the exhaust cam 3363, and the intake valve driving member 6 comprises the first driving member 61 and the second driving member 62, and further, the bore 613 of the first driving member 61 and the bore 623 of the second driving member 62 are in communication with each other to form the hydraulic cylinder 64, with the spring 642 and the first piston 643 and the second piston 644 that are movable hydraulically and by the spring 642 being contained within the hydraulic cylinder 64, the first driving member 61 and the second driving member 62 are selectively rotatable independent of each other or in combination with each other to vary lift stroke of the intake valve 332 of the engine 3, and thus simplifying engineering of variable lift for the engine valve 332 of the engine 3. Further, with the positioning bars 612, 622 of the first driving member 61 and the second driving member 62 located between the positioning holes 611, 621 and the pressing section 625 and with the bores 613, 623 of the first driving member 61 and the second driving member 62 located between the push rollers 613, 6232 and the positioning holes 611, 621 and located above the center-connection line A connecting between centers of the push rollers 614, 624 and the positioning holes 611, 621, the overall height of the cylinder head 33 is effectively reduced.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 

1. A driving member of valve of engine, the engine comprising a crankcase, a cylinder block mounted on the crankcase, and a cylinder head mounted on the cylinder block, the cylinder head comprising an intake port and an intake valve and an exhaust port and an exhaust valve, a camshaft seat being arranged between the intake valve and the exhaust valve, the camshaft seat comprising a camshaft that is driven by a timing chain, the camshaft comprising a first intake cam, a second intake cam, and an exhaust cam mounted thereto, whereby through the first intake cam, the second intake cam, and the exhaust cam, the camshaft, when put in rotation, drives an intake valve driving member or an exhaust valve driving member, and further, through the intake valve driving member or the exhaust valve driving member, the intake valve or the exhaust valve is caused to operate, characterized in that the intake valve driving member comprises a first driving member and a second driving member, the first driving member forming a positioning hole, a bore, and a push roller, the second driving member forming a positioning hole, a bore, a push roller, and a pressing section, the positioning holes of the first driving member and the second driving member receiving extension of a shaft rod therethrough, the push roller of the first driving member being in engagement with the first intake cam, the push roller of the second driving member being in engagement with the second intake cam, the pressing section of the second driving member being in engagement with the intake valve, the bore of the first driving member and the bore of the second driving member being in communication with each other to form a hydraulic cylinder, whereby the hydraulic cylinder allows the first driving member and the second driving member to operate independent of each other in a low lift opening condition of the intake valve and allows the first driving member and the second driving member to operatively connect to each other in a high lift opening condition of the intake valve.
 2. The valve driving member of engine according to claim 1, wherein the cylinder head comprises an oil control valve.
 3. The valve driving member of engine according to claim 1, wherein the cylinder head comprises a position-constraining mechanism in pushing engagement with the first driving member and the second driving member, the position-constraining mechanism comprising a position-constraining rod, a spring, and a pressure relief hole.
 4. The valve driving member of engine according to claim 3, wherein the first driving member and the second driving member comprise positioning bars, the positioning bars being in pushing engagement with the position-constraining rod of the position-constraining mechanism.
 5. The valve driving member of engine according to claim 4, wherein the positioning bars of the first driving member and the second driving member are located between the positioning holes and the pressing section.
 6. The valve driving member of engine according to claim 1, wherein the bores of the first driving member and the second driving member are located between the push rollers and the positioning holes and are located above a center-connection line connecting between centers of the push rollers and the positioning holes.
 7. The valve driving member of engine according to claim 1, wherein the first driving member and the second driving member are formed integrally.
 8. The valve driving member of engine according to claim 4, wherein the first driving member and the second driving member are formed integrally.
 9. The valve driving member of engine according to claim 6, wherein the first driving member and the second driving member are formed integrally.
 10. The valve driving member of engine according to claim 1, wherein the pressing section comprises a gap adjusting member.
 11. The valve driving member of engine according to claim 5, wherein the pressing section comprises a gap adjusting member.
 12. The valve driving member of engine according to claim 1, wherein the hydraulic cylinder has two ends respectively closed by closure caps and receives therein a spring, the first piston, and the second piston.
 13. The valve driving member of engine according to claim 12, wherein the first piston forms a first recess and a second recess.
 14. The valve driving member of engine according to claim 13, wherein the closure caps form projecting pegs projecting inward of the hydraulic cylinder. 